57b08b0944
to reflect the new license. These used slightly different spellings that defeated my regular expressions. We understand that people may be surprised that we're moving the header entirely to discuss the new license. We checked this carefully with the Foundation's lawyer and we believe this is the correct approach. Essentially, all code in the project is now made available by the LLVM project under our new license, so you will see that the license headers include that license only. Some of our contributors have contributed code under our old license, and accordingly, we have retained a copy of our old license notice in the top-level files in each project and repository. llvm-svn: 351648
158 lines
4.4 KiB
C++
158 lines
4.4 KiB
C++
// -*- C++ -*-
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//===------------------------------ bit ----------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===---------------------------------------------------------------------===//
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#ifndef _LIBCPP_BIT
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#define _LIBCPP_BIT
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/*
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bit synopsis
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namespace std {
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} // namespace std
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*/
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#include <__config>
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#include <version>
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#if defined(__IBMCPP__)
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#include "support/ibm/support.h"
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#endif
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#if defined(_LIBCPP_COMPILER_MSVC)
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#include <intrin.h>
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#endif
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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#pragma GCC system_header
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#endif
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_LIBCPP_BEGIN_NAMESPACE_STD
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#ifndef _LIBCPP_COMPILER_MSVC
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inline _LIBCPP_INLINE_VISIBILITY
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int __ctz(unsigned __x) { return __builtin_ctz(__x); }
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inline _LIBCPP_INLINE_VISIBILITY
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int __ctz(unsigned long __x) { return __builtin_ctzl(__x); }
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inline _LIBCPP_INLINE_VISIBILITY
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int __ctz(unsigned long long __x) { return __builtin_ctzll(__x); }
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inline _LIBCPP_INLINE_VISIBILITY
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int __clz(unsigned __x) { return __builtin_clz(__x); }
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inline _LIBCPP_INLINE_VISIBILITY
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int __clz(unsigned long __x) { return __builtin_clzl(__x); }
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inline _LIBCPP_INLINE_VISIBILITY
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int __clz(unsigned long long __x) { return __builtin_clzll(__x); }
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inline _LIBCPP_INLINE_VISIBILITY
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int __popcount(unsigned __x) { return __builtin_popcount(__x); }
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inline _LIBCPP_INLINE_VISIBILITY
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int __popcount(unsigned long __x) { return __builtin_popcountl(__x); }
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inline _LIBCPP_INLINE_VISIBILITY
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int __popcount(unsigned long long __x) { return __builtin_popcountll(__x); }
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#else // _LIBCPP_COMPILER_MSVC
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// Precondition: __x != 0
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inline _LIBCPP_INLINE_VISIBILITY
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int __ctz(unsigned __x) {
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static_assert(sizeof(unsigned) == sizeof(unsigned long), "");
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static_assert(sizeof(unsigned long) == 4, "");
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unsigned long __where;
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if (_BitScanForward(&__where, __x))
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return static_cast<int>(__where);
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return 32;
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}
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inline _LIBCPP_INLINE_VISIBILITY
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int __ctz(unsigned long __x) {
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static_assert(sizeof(unsigned long) == sizeof(unsigned), "");
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return __ctz(static_cast<unsigned>(__x));
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}
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inline _LIBCPP_INLINE_VISIBILITY
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int __ctz(unsigned long long __x) {
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unsigned long __where;
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#if defined(_LIBCPP_HAS_BITSCAN64)
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(defined(_M_AMD64) || defined(__x86_64__))
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if (_BitScanForward64(&__where, __x))
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return static_cast<int>(__where);
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#else
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// Win32 doesn't have _BitScanForward64 so emulate it with two 32 bit calls.
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if (_BitScanForward(&__where, static_cast<unsigned long>(__x)))
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return static_cast<int>(__where);
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if (_BitScanForward(&__where, static_cast<unsigned long>(__x >> 32)))
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return static_cast<int>(__where + 32);
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#endif
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return 64;
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}
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// Precondition: __x != 0
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inline _LIBCPP_INLINE_VISIBILITY
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int __clz(unsigned __x) {
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static_assert(sizeof(unsigned) == sizeof(unsigned long), "");
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static_assert(sizeof(unsigned long) == 4, "");
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unsigned long __where;
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if (_BitScanReverse(&__where, __x))
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return static_cast<int>(31 - __where);
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return 32; // Undefined Behavior.
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}
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inline _LIBCPP_INLINE_VISIBILITY
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int __clz(unsigned long __x) {
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static_assert(sizeof(unsigned) == sizeof(unsigned long), "");
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return __clz(static_cast<unsigned>(__x));
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}
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inline _LIBCPP_INLINE_VISIBILITY
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int __clz(unsigned long long __x) {
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unsigned long __where;
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#if defined(_LIBCPP_HAS_BITSCAN64)
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if (_BitScanReverse64(&__where, __x))
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return static_cast<int>(63 - __where);
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#else
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// Win32 doesn't have _BitScanReverse64 so emulate it with two 32 bit calls.
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if (_BitScanReverse(&__where, static_cast<unsigned long>(__x >> 32)))
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return static_cast<int>(63 - (__where + 32));
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if (_BitScanReverse(&__where, static_cast<unsigned long>(__x)))
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return static_cast<int>(63 - __where);
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#endif
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return 64; // Undefined Behavior.
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}
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inline _LIBCPP_INLINE_VISIBILITY int __popcount(unsigned __x) {
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static_assert(sizeof(unsigned) == 4, "");
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return __popcnt(__x);
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}
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inline _LIBCPP_INLINE_VISIBILITY int __popcount(unsigned long __x) {
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static_assert(sizeof(unsigned long) == 4, "");
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return __popcnt(__x);
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}
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inline _LIBCPP_INLINE_VISIBILITY int __popcount(unsigned long long __x) {
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static_assert(sizeof(unsigned long long) == 8, "");
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return __popcnt64(__x);
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}
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#endif // _LIBCPP_COMPILER_MSVC
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP_BIT
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